The present invention relates to a weather strip for a vehicle, for example, a trim to be used for the weather strip or a decorative member and an insert for the trim embedded in a body made of polymer material such as rubber, elastomer and resin to retain the shape of the trim. The present application is based on Japanese Patent Application No. 2000-332857, which is incorporated herein by reference.
As a trim of this kind, there has been known a structure in which an insert formed of a metal plate for retaining the shape of a trim body made of polymer material such as rubber, elastomer and resin and maintaining the gripping force of gripping lips to grip a flange portion of a vehicle body is embedded in the trim body. The trim body is bent to have a substantially U-shaped cross-section and the gripping lips for gripping the flange portion around an opening of the vehicle are protruded from the internal surface of the trim body. A weather strip has the trim body attached to the flange portion around the opening of the vehicle body, and a hollow sealing portion being protruded from the outer surface of the trim body, for example, the outer surface of a side portion outwardly and serving to seal the inside and outside of the vehicle cabin.
As such an insert embedded in the trim, for example, there has been known a flat insert having a plurality of rectangular planar segments coupled through one coupling portion in central parts thereof (a first conventional structure). Moreover, there has also been known a flat insert having a plurality of rectangular planar segments coupled through two coupling portions separated from each other at a predetermined interval (a second conventional structure). As shown in FIG. 6A, furthermore, there has also been known an insert 53 in which a bent wire 51 is connected through two longitudinal members 52 in a predetermined position (a third conventional structure). FIG. shows a state in which the insert 53 having the third conventional structure is embedded in polymer material and is bent to have a U-shaped cross-section. Each of the inserts of first and second conventional structure is also bent to have a U-shaped cross-section and is embedded in polymer material.
In addition, for example, Unexamined Japanese Patent Publication Sho. 53-136225 (U.S. Pat. No. 4,196,546) has also disclosed an insert 60 (a fourth conventional structure). In the insert 60, as shown in FIG. 7A, a metal plate 61 has a first series of slits 62 arranged in a central part thereof with a predetermined interval in a longitudinal direction of the metal plate 61 and a pair of second series of slits 64 also arranged in the longitudinal direction with a predetermined interval in the vicinity of both edge portions 63. By press rolling both edge portions 63 of the metal plate 61 through a pair of rollers, as shown in FIG. 7B, there is formed the insert 60 in which segments 65 are separated from each other and are coupled through oblique coupling links 66.
The trim is usually mounted with bending along the curvature of a flange portion of an opening of the vehicle in such a state that it is cut to have a predetermined length. Although the trim including the insert having the first conventional structure can be bent along the curvature of the flange portion, it has poor contracting and extending properties in the longitudinal direction thereof since one coupling portion located at the central part prevents contracting and extending of the insert. For this reason, it is necessary to strictly manage the length of the trim corresponding to the circumference of the flange portion in order not to generate a clearance between the ends of the mounted trim. Moreover, there has been a problem in that a countermeasure cannot be taken against the case in which the circumference of the flange portion is increased due to a set of tolerances.
Moreover, the trim including the insert having the second conventional structure is generally covered with polymer material and at least one of two coupling portions is cut for use. Consequently, as similar to the aforementioned first conventional structure, while the following property for the flange portion is maintained, the contracting property in the longitudinal direction of the trim is poor so that the length of the trim is to be managed strictly. On the other hand, in such a trim, some extending property is maintained in the longitudinal direction and a countermeasure can easily be taken against the case in which the circumference of the flange portion is increased by the set of tolerances.
However, when the trim is particularly mounted on the flange portion in a bending and an extension state in a position corresponding to the corner portion of the body opening, a residual stress is generated in the trim in some cases. If such a residual stress is present, the trim mounted on the flange portion is apt to be contracted and deformed to gradually restore to an original extrusion state (straight state) by the elastic force of the polymer material itself. Consequently, there has been a problem in that the trim is shifted carelessly from the flange portion at a predetermined position in a slip-off direction, resulting in poor appearance.
On the other hand, the trim including the insert 53 having the third conventional structure is controlled to be extended in the longitudinal direction thereof due to the presence of the longitudinal members 52. In the trim, moreover, contraction in the longitudinal direction is permitted by the deflection of the bent wire 51 and the longitudinal members 52. Consequently, the trim is cut to be slightly longer than the circumference of the flange portion and is mounted in a slight contraction state. Thus, the trim can easily be mounted on the flange portion without generating the residual stress and the clearance, and the appearance of the trim can be enhanced.
In the trim including the insert 53 having the third conventional structure, however, there has been a problem in that the structure of the insert 53 is complicated, a great deal of time and labor is required for forming and the manufacturing cost is greatly increased. Moreover, there has been a problem in that the rigidity is liable to be insufficient because the insert 53 is mainly constituted by the bent wire 51.
Further, the trim including the insert 60 having the fourth conventional structure is covered with polymer material. And the insert 60 is made that portions of both edge portions 63 thinned by press rolling which correspond to the second slit 64 are cut for use. Also in such a trim, the coupling links 66 coupling the adjacent segments 65 are inclined in the same direction with respect to the segment 65 when the insert 60 is bent to have a U-shaped cross-section. For this reason, when the trim is contracted in a longitudinal direction, the coupling links 66 are slightly deformed in such a manner that the coupling links 66 tend to be parallel with the segments 65. Consequently, the distance between the adjacent segments 65 is slightly reduced so that the whole trim is contracted.
In the insert 60 having the fourth conventional structure, however, the coupling links 66 are simply formed to be oblique to the segment 65. For this reason, there has been a problem in that the deformation of the coupling links 66 is not stabilized when the trim is contracted in the longitudinal direction thereof, and the contracting property of the trim is easily varied.
In consideration of the problems of the conventional insert, this invention has been made. The invention has an object to provide an insert for a trim which can easily be formed, can have a high tensile strength substantially with no elongation and can be contracted stably in the longitudinal direction of the trim, the trim and a weather strip with a trim body for a vehicle.
In order to achieve the object, a first aspect of the invention is an insert for a trim formed of a metal plate which is to be embedded in polymer material of the trim and comprises a plurality of segments and a pair of coupling portions mutually coupling two adjacent segments at a predetermined interval, wherein the coupling portions extend obliquely to the associated segments, and a cut-out portion, or notch, is provided in at least one acute corner of the junctions between each coupling portion and the associated segments.
In the insert for a trim according to the first aspect of the invention, the coupling portions connecting the adjacent segments are inclined in the same direction with respect to the segments when the insert is bent to have a U-shaped cross-section. Therefore, when the contraction force acts in the longitudinal direction of the insert, each of coupling portions is slightly deformed in such a manner that the coupling portion tends to be parallel with the segments. The cut-out portion is provided in at least one of the acute corners of the junctions between each coupling portion and the associated segments. Consequently, when the contraction force acts on the insert, each of the coupling portions is deformed by using the cut-out portion as an origin and the deformation of the coupling portion is stabilized. On the other hand, even if tensile force acts in the longitudinal direction of the insert, obtuse corners in the junctions between each coupling portion and the associated segments will resist deformation, and it is possible to prevent deformation in such a manner that the coupling portion tends to be perpendicular to the segments. Consequently, the insert can be contracted with substantially no elongation. Moreover, the insert can maintain a high tensile strength and can easily be formed by punching a flat metal plate, for example.
Further, a second aspect of the invention is the insert for a trim according to the first aspect of the invention, wherein the cut-out portion is provided on the segment at the acute corner and at least a part of an inner peripheral surface thereof is formed continuously with a side of the coupling portion.
In the insert for a trim according to the second aspect of the invention, in addition to the function of the first aspect of the invention, when contraction force acts in the longitudinal direction of the insert, the coupling portion can be more reliably deformed in such a manner that the coupling portion tends to be in parallel with the segment.
Furthermore, a third aspect of the invention is the insert for a trim according to the second aspect of the invention, wherein the cut-out portion is formed such that an inner peripheral surface thereof constitutes a part of a substantially cylindrical surface.
In the insert for a trim according to the third aspect of the invention, in addition to the function of the second aspect of the invention, when the contraction force acts in the longitudinal direction of the insert, a stress does not converge on a part of the inner peripheral surface of the cut-out portion but the coupling portion can be deformed more stably.
Moreover, a fourth aspect of the invention is the insert for a trim according to any of the first to third aspects of the invention, wherein the coupling portions are formed such that inclinations to the segment are alternately inverted through the segment.
In the insert for a trim according to the fourth aspect of the invention, in addition to the function of any of the first to third aspects of the invention, the directions of movement of the adjacent segments with the deformation of the coupling portion are reverse to each other. Consequently, the amount of the deformation of the whole insert can be reduced.
Furthermore, a fifth aspect of the invention is the insert for a trim according to any of the first to fourth aspects of the invention, wherein the coupling portions are connected to the segments in positions where distances from edges of the segments in the transverse direction are different from each other, respectively.
In the insert for a trim according to the fifth aspect of the invention, in addition to the function of any of the first to fourth aspects of the invention, the position of a bending neutral axis in the trim can be controlled by regulating the position of both coupling portions. Consequently, also in the case in which the insert is applied to the weather strip having a large protruded portion such as a seal portion provided in the side portion of the trim, for example, the bending neutral axis can be set to cancel the inclination of the trim which is caused by the balance of the whole weather strip.
Moreover, a sixth aspect of the invention is a trim comprising a trim body formed of polymer material which embeds an insert therein and is bent to have a substantially U-shaped cross-section, wherein the insert is constituted by the insert for a trim according to any of the first to fifth aspects of the invention.
In the trim according to the sixth aspect of the invention, it is possible to easily mount the trim to the flange portion with good appearance without strictly managing the length of the trim itself for the whole circumference of the flange portion for attachment and generating a clearance between both ends in the flange portion.
Furthermore, a seventh aspect of the invention is directed to a weather strip comprising a trim body formed of polymer material which embeds an insert therein and is bent to have a substantially U-shaped cross-section and a seal portion protruded from an outer surface of the trim body, wherein the insert is constituted by the insert for a trim according to any of the first to fifth aspects of the invention.